Process of producing substituted malonylchlorides



Patented Apr. 2, 1946 2 UNITED STATES PATENT OFFICE mocass 3E nfirm sgg s'rlm'mn Digs-Ii; S. Kharasch, Chicago, 111., assignor to Eli poratlon oi In and Company, Indianapolis, Incl, a com-- diana No Drawing. Application May 24, 1943, Serial No. 488,233

BClaims.

It is the object of my invention to produce substituted malonylchlorides by a simple, effective, and economical reaction.

Such malonylchlorides are represented by the following formula:

in which R is a lower aliphatic hydrocarbon radical (by which I mean one having not more than 6 carbon atoms). and R" is either a hydrogen atom or a lower aliphatic hydrocarbon radical. When both R and R" are aliphatic hydrocarbon radicals, they may be interconnected in a polymethylene or substituted-polymethylene chain to form a ring structure. When R and R" are thus intercom. acted to form a ring structure, the compounds are represented by the following formula:

R ME L01 (2) (R--R) I C R-JJ CC1 in which R represents a lower aliphatic hydrocarbon radical, malonyl chlorides having the formula:

R C--Cl in which each of R and R. represents a lower aliphatic hydrocarbon radical, and malonyl chlorides having the formula:

2 i a- -01 5 (s (Ed-#0 a-i 0-0 m in which R is a member of the class consisting oi hydrogen and lower aliphatic hydrocarbon radicals, and n is a whole number between 1 and 4 inclusive.

In the following description and in the claims I use certain terms in referring to hydrogen atoms. The terms are defined as follows:

a. By "primary hydrogen atom" I mean a hydrogen atom directly attached to a primary carbon atom.

b. By "secondary hydrogen atom" I mean a hydrogen atom directly attached to a secondary carbon atom.

o. By tertiary hydrogen atom" I mean a hydrogen atom directly attached to a tertiary car bon atom.

d. By "aprimary hydrogen atom I mean a hydrogen atom of the class consisting of secondary and tertiary hydrogen atoms.

The claims of the present application are limited to exclude the compounds 01' Formula 3, and to include in the compounds of Formula 5 only those compounds in which at least one R on any carbon atom is hydrogen.

The method of producing substituted malonylchlorides in accordance with the present invention is to replace a secondary or tertiary hydrogen atom on the a-carbon atom of an acid chloride by a chloroformyl group with the aid of phosgene or diphosgene. The reaction with phosgene is represented by the following equation:

The reaction with diphosgene is represented by the following equation: l

In these equations R. and R" have the same 601 8511111: as before.

acid chlorides having the formula:

and acid chlorides having the formula:

in which formulas R), R, R, and n have the same meanings as before.

In order that the reaction proceed, it is necessary that a hydrogen atom on the a-carbon atom oi the initial acid chloride be aprimary that is, either secondary or tertiary-for if it is primary there is no reaction. The best yields, however, (about 70-85 percent), are obtained if the hydrogen on the a-carbon atom of the acid chloride is tertiary.

This may be illustrated by the following:

a. If acetyl chloride is treated with phosgene or diphosgene, even at high temperature no perceptible reaction occurs; for here the hydrogen atoms on the a-carbon atom of the acid chloride are all primary. This is indicated by the following equation:

H o A: (I1: beat (11) H- -Cl+ 000i: no reaction b. If propionyl chloride is treated with phosgene or diphosgene, at elevated temperature, a fair yield (20-30 percent) of monomethyimalonylchloride is obtained, for here the two hydrogen atoms on the a-carbon atom are secondary. This is indicated by the following equation:

H O H C-Ci J: 3% heat (i2) CH1- C1 0001, --0 C\ C fi-Cl (about 20 percent yield) c. If isobutyryl chloride is treated with phosgene or diphosgene, at elevated temperature, an excellent yield (85-90 percent) of dimethylmalonylchloride is obtained, for here the hydrogen atom on the a-carbon atom is tertiary. This is indicated by the following equation:

(about 86-00 percent yield) From this set 0! Equations i1, 12, and 13 it is apparent at. That a chloroiormyi group derived from phosgene or diphosgene replaces very readily a tertiary hydrogen atom on the a-carbon atom of an acid chloride;

b. That it replaces with considerable difllculty (taking low yield as a criterion) a secondary hydrogen atom on the a-carbon atom of an acid chloride; and

c. That it does not replace at all a primary hydrogen atom on the a-carbon atom of an acid chloride.

My process is therefore of particular advantage in the obtaining of substituted malonylchlorides by the treatment with phosgene or diphosgene of acid chlorides in which the z-carbon is tertiary.

Thus:

Phosgene or dlphosgene reacts at elevated temperature with isobutyrylchloride to give an 85-90 percent yield of dlmethylmalonylchloride; as is shown by Equation 13 above.

Phosgene or diphosgene reacts at elevated temperature with a-ethylbutyrylchlorlde to give about a percent yield of diethylmalonylchloride.

Phosgene or diphosgene reacts at elevated temperature with a-ethylhexoylchloride to give a high yield of ethylbutylmalonyichloride.

Phosgene or diphosgene reacts at elevated temperature with hexahydrobenzoylchloride to give a 90 percent yield of 1,1-dichloroformylcyclohexone; which may also be called a,a-(1,5-Denl;a methylene) malonylchlorlde.

In obtaining the last-named product, it is not necessary to start with hexahydrobenzoylchloride. If desired, the starting compound may be cyclohexane. Under optimum conditions, of 6 hours heating at 225 C. of cyclohexane with diphosgene, the disubstitution product 1,1-dichloroformylcyclohexane is obtained. While unquestionably hexahydrobenzoylchloride must have been produced as an intermediate, yet on careful search no hexahydrobenzoylchloride could be detected in the final product. Thus it is apparent that diphosgene reacts more readily with hexahydrobenzoylchloride than with cyclohexane, and converts quite readily to 1,1-dichloroformylcyclohexane all hexahydrobenzoylchloride that is difflcultly produced from cyclohexane.

In all the reactions indicated above, it is desirable that the reaction be carried out at high temperature, of the order of 200-300 C., for several hours; and it is desirable that the reaction be carried out under pressure, conveniently in a bomb if it is done by a batch process.

I claim as my invention:

1. The process of producing disubstituted malonylchlorides, which consists in treating with a reagent of the class consisting of phosgene and diphosgene, under pressure and at high temperature, an acid chloride of the class consisting oi acid chlorides having the following formula:

aliphatic hydrocarbon radical, and acid chlorides having the following formula:

11 o 3- L01 a-timc in i i-Cl a: E-ci in which R and R represent a lower aliphatic hydrocarbon radical; which substituents each having not more than 6 carbon atoms; which consists in treating with a reagent of the class consisting of phosgene and diphosgene, under pressure and at high temperature, an acid chloride having the following formula:

in which R and RF have the same meaning as before.

4. The process of producing dimethylmalonylchloride, which consists intreating isobutyrylchloride, under pressure and at high temperature, with a reagent of the class consisting of phosgene and diphosgene,

5. The process of producing diethylmalonylchloride, which consists in treating a-ethylbutyrylchloride, under pressure and at high temperature, with a reagent of the class consisting of phosgene and diphosgene.

6. The process of producing a malonylchloride of the following formula:

H 0 at Let t R-k 0-01 in which R represents a member of the class consisting of hydrogen and lower aliphatic radicals, and n represents a whole number between 1 and 4 inclusive; which consists in treating with a reagent of the class consisting of phosgene and diphosgene, under pressure and at high temperature, an acid chloride having the following formula:

0 3.? as (ll-5R0 in which R and n have the same meaning as before.

MORRIS S. W.

Certificate of Correction Patent N0. 2,397,669.

April 2, 194a.

MORRIS S. KHARASGH It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

"which insert each of; same line, for

represent read represents;

line 19 after Page 3, first column,

20, strilre out line substituenta each and insert instead con-; line 21, strike out having not more than 6 carbon atoms; which con-; and second column,

line 14, claim 6, for that portion of the formula reading (R-OR), read (RGH),; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 18th day of June, A. D. 1946.

LESLIE FRAZER,

First Assistant Commissioner of Patents.

in i i-Cl a: E-ci in which R and R represent a lower aliphatic hydrocarbon radical; which substituents each having not more than 6 carbon atoms; which consists in treating with a reagent of the class consisting of phosgene and diphosgene, under pressure and at high temperature, an acid chloride having the following formula:

in which R and RF have the same meaning as before.

4. The process of producing dimethylmalonylchloride, which consists intreating isobutyrylchloride, under pressure and at high temperature, with a reagent of the class consisting of phosgene and diphosgene,

5. The process of producing diethylmalonylchloride, which consists in treating a-ethylbutyrylchloride, under pressure and at high temperature, with a reagent of the class consisting of phosgene and diphosgene.

6. The process of producing a malonylchloride of the following formula:

H 0 at Let t R-k 0-01 in which R represents a member of the class consisting of hydrogen and lower aliphatic radicals, and n represents a whole number between 1 and 4 inclusive; which consists in treating with a reagent of the class consisting of phosgene and diphosgene, under pressure and at high temperature, an acid chloride having the following formula:

0 3.? as (ll-5R0 in which R and n have the same meaning as before.

MORRIS S. W.

Certificate of Correction Patent N0. 2,397,669.

April 2, 194a.

MORRIS S. KHARASGH It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

"which insert each of; same line, for

represent read represents;

line 19 after Page 3, first column,

20, strilre out line substituenta each and insert instead con-; line 21, strike out having not more than 6 carbon atoms; which con-; and second column,

line 14, claim 6, for that portion of the formula reading (R-OR), read (RGH),; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 18th day of June, A. D. 1946.

LESLIE FRAZER,

First Assistant Commissioner of Patents. 

